OK,..BB heaters. The breakers,..are they two pole(240Volt) ?. Hook is correct Breakers rarely fail, especially 3 at once. They are NOT your problem. Do the BB heaters have 'on board' T stats or is there Tstats on the wall somewhere. U have to check for power at the heaters (with the cover off) and then work back thru the circuit ending up at your panel. U could also start at the panel(breaker terminals BE CAREFUL) and work forward thru the circuit, watever ya like. Buy yourself a cheap tester...NOT a meter. U don't need a meter, just a voltage tester. .....Just a cheapy will be fine. Once u have a tester, i will help u figure all this out OK. Up to u bud...we can do this, but u need a tester and a few screwdrivers....
We can do it all thru WA with face time.....